The effect of in vitro ã-irradiation on mitogenic responsiveness of murine lymphocytes

The objective of this study was to analyze the proliferative response of BALB/cmice lymphocytes after in vitro irradiation (0.05 to 6 Gy). The capability of irradiatedlymphocytes for proliferating without any stimulation and after activation withspecific T and B cell mitogens has been evaluated. The results show that ionizingradiation significantly inhibits spontaneous cellular proliferation and that induced bymitogens and that variations in the degree of inhibition are found depending on theinducing proliferation mitogens and the dosage applied. The conclusion drawn is thatdifferent lymphocyte populations have different radiosensitivities, being B cells moresensitive to ionizing irradiation than T cells. Besides, the effects of gamma-irradiationvary according to the different subpopulations of T cells or, alternatively, to differentT-dependent activation mechanisms (AU)

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The effect of in vitro gamma-irradiation on mitogenic responsiveness of murine lymphocytes.

The objective of this study was to analyze the proliferative response of BALB/c mice lymphocytes after in vitro irradiation (0.05 to 6 Gy). The capability of irradiated lymphocytes for proliferating without any stimulation and after activation with specific T and B cell mitogens has been evaluated. The results show that ionizing radiation significantly inhibits spontaneous cellular proliferation and that induced by mitogens and that variations in the degree of inhibition are found depending on the inducing proliferation mitogens and the dosage applied. The conclusion drawn is that different lymphocyte populations have different radiosensitivities, being B cells more sensitive to ionizing irradiation than T cells. Besides, the effects of gamma-irradiation vary according to the different subpopulations of T cells or, alternatively, to different T-dependent activation mechanisms.

Dissociation of lung function, dyspnea ratings and pulmonary extension in bronchiectasis.

UNLABELLED: Bronchiectasis is a heterogeneous disease in terms of its clinical and functional presentation. Some isolated parameters have been used to assess the severity of bronchiectasis or its response to treatment. A study was undertaken to evaluate whether lung function, dyspnea and extension of the disease are separate entities in the impact of bronchiectasis upon patients using factor analysis. Patients with bronchiectasis diagnosed by high-resolution computed tomography (HRCT) and airflow obstruction defined by FEV1/FVC<70% were included. Data were collected relating to clinical history, three different clinical ratings of dyspnea (Medical Research Council (MRC), Borg scale and Basal Dyspnea Index), the extent of bronchiectasis and functional variables. A total of 81 patients (mean age (SD): 69.5 (8.7)) years were included. The degree of dyspnea (MRC) was 1.9 (0.8). Mean FEV1 was 1301 ml (56.9% pred.). Four factors were found that accounted for 84.1% of the total data variance. Factor 1 (45.6% of the data variance) included the three measurements of dyspnea. Factor 2 (16% variance) comprised airflow obstruction parameters (FEV1, FEV1/FVC and PEF). Factor 3 (13.8% variance) included RV/TLC and RV (lung hyperinflation). Factor 4 (8.6% variance) included bronchiectasis extent. Dyspnea was more closely correlated with lung hyperinflation (r:0.33-0.54) than with airflow obstruction parameters (r:0.17-0.26). CONCLUSIONS: Airflow obstruction, dyspnea, lung hyperinflation and the lung extent of the bronchiectasis are four independent entities in the impact of bronchiectasis upon patients.

Effects of nordihydroguaiaretic acid on murine antibody-dependent cellular cytotoxicity.

The purpose of this study was to analyze the effects of nordihydroguaiaretic acid, an inhibitor of the lipoxygenase pathway of arachidonic acid, on antibody-dependent cellular cytotoxicity. Antibody-dependent cellular cytotoxicity mediated by murine spleen cells was significantly inhibited by concentrations of nordihydroguaiaretic acid from 10(-5) to 10(-4) M (1C50 = 2 x 10(-5) M). The inhibitory effect of nordihydroguaiaretic acid was also observed on antibody-dependent cellular cytotoxicity mediated by macrophage-depleted spleen cells as well as isolated macrophages. Nordihydroguaiaretic acid was highly effective when added at the beginning of the assay and was always present throughout the assay, but failed to inhibit the binding of effector and target cells. The inhibition produced by nordihydroguaiaretic acid could not be reversed by leukotriene B4, a 5-lipoxygenase product. These results suggest that arachidonic acid metabolites other than leukotriene B4 are released by different populations of spleen cells to positively regulate important events in the postbinding phase of murine antibody-dependent cellular cytotoxicity.

Seasonal variation in proliferative response and subpopulations of lymphocytes from mice housed in a constant environment.

A seasonal variation in the proliferative response to mitogens and in the proportion of splenic lymphocyte subpopulations was found in mice housed in a constant environment. The lymphoproliferative responses to T-cell and B-cell mitogens reached maximum values in autumn and summer. Identification of lymphocyte subpopulations by flow cytometry demonstrated that the proportion of T cytotoxic-suppressor (Tcs) lymphocytes was significantly higher in autumn and summer than in spring and winter. However, the proportion of B lymphocytes was significantly lower in spring than in the other three seasons, whereas the proportions of T and T helper (Th) cells did not show any seasonal variation. On the other hand, we observed a significant correlation between the level of mitogenic responsiveness and the proportion of Tcs cells, but not between the former and the proportions of B, T or Th cells. These data suggest that the seasonal variation in murine lymphoproliferative responses may depend on the cyclic changes in the proportion of Tcs lymphocytes; these changes, in turn, may be predetermined by the inherent internal biological rhythms of the animal.

Differential effects of the calcium ionophore A23187 and the phorbol ester PMA on lymphocyte proliferation.

The effects of the phorbol ester, phorbol-12-myristate-13-acetate (PMA), and of the calcium ionophore A23187 on DNA synthesis in murine quiescent and mitogen-stimulated lymphocytes have been examined. Neither PMA nor A23187 had any mitogen effect on their own on quiescent lymphocytes. However, stimulation of cells sequentially with A23187 and then PMA resulted in a proliferative response in proportion to the duration of the exposure to A23187, and the sustained simultaneous presence of both agents was necessary for maximum proliferation. On the other hand, while short incubations with A23187 potentiated mitogen-induced DNA synthesis, prolonged exposure inhibited it. Furthermore, on lymphocytes stimulated with two T cell mitogens, the effects of A23187 and PMA depended on the proliferation-inducing mitogens and the responsiveness level induced by them. Therefore, while PMA and short pretreatments with A23187 had no effect on high intensity mitogenic responses, low intensity responses were significantly enhanced. These results demonstrate differential effects of A23187 and PMA on DNA synthesis that should be useful in studies on the mechanisms of activation of lymphocyte proliferation.

Effects of lipoxygenase and cyclooxygenase inhibitors on murine antibody-dependent cellular cytotoxicity (ADCC).

The purpose of this study was to determine the effects that specific inhibition of arachidonic acid (AA) metabolism has on the antibody-dependent cellular cytotoxicity (ADCC) of murine spleen cells. The action of three inhibitors of the lipoxygenase (LO) pathway--nordihydroguaiaretic acid (NDGA), esculetin (Es), and phenanthroline (Phe)--was compared with that of three inhibitors of the cyclooxygenase (CO) pathway--indomethacin (INDO), acetyl salicylic acid (ASA), and imidazole (IMI). All the LO inhibitors suppressed ADCC function in a dose-dependent manner, but NDGA was the most potent inhibitor of this cytolytic activity. In fact, NDGA inhibited the ADCC function with 97% inhibition at 100 microM, while Phe and Es, at the same concentration, inhibited ADCC by 21% and 19%, respectively. However, CO inhibitors did not markedly affect ADCC function and only some doses of them had a slight, but significant, depressing effect (8-11% inhibition at 0.01-0.1 microM of INDO, 7% inhibition at 400 microM of ASA, and 13% inhibition at 800-1000 microM of IMI). These results suggest the LO pathway of the arachidonic acid metabolism plays an important role in regulating ADCC activity of murine spleen cells and the products of the CO pathway have little effect on ADCC lysis.

A study of lymphocyte populations and subpopulations in hemophiliacs and their relationships with age and consumption of lyophilized factor VIII concentrates.

Peripheral blood lymphocyte populations and subpopulations of 154 hemophiliacs treated with factor VIII concentrates were studied. The patients had significantly increased percentages of leukocytes and lymphocytes and also absolute numbers of the lymphocyte populations in cells/mm3. The increases in cell counts in the two major T cell subpopulations (T4 and T8) were unbalanced, leading to a significant decrease in the T4/T8 ratio. There was no correlation between the T4/T8 ratio and the consumption of factor VIII during the year prior to the study. The values of these T cell subpopulations and of the T4/T8 ratio significantly correlated with the patient's age. There were no analytical or clinical data for any of the patients indicating AIDS.

Mechanism of suppression of the depressed lymphocyte response in lung cancer patients.

We studied the function of monocyte-mediated suppression in the proliferative responses of depressed T-cells of patients with advanced lung cancer, with both local (Stage III) and extrapulmonary metastasis (Stage IV). The mononuclear cells of 13 non-treated patients showed a significant drop in proliferation upon stimulation with suboptimum, optimum and supraoptimum doses with regards to normal controls (p less than 0.001). On treating T-cells with indomethacin, lymphoblastic transformation increased in both groups (patients and controls), but was significantly greater in the patient group (p less than 0.001). The lipopolysaccharide (LPS) exerted an inhibitory effect on the suppressor cells of normal individuals, yet failed to do so in the case of patients treated either with or without indomethacin. The stimulation of the patients mononuclear cells with PWM failed to increase proliferation, and was not affected by either indomethacin of LPS. Our conclusions are as follows: Patients with lung cancer present a drop in mononuclear cell proliferation when stimulated with PHA; This phenomenon may be due to an exacerbation of the immune systems suppressor function; One of the suppressor mechanisms is prostaglandin-dependent and mediated by monocytes; The B-cells have no relevant functions.

Detection of Aspergillus antigen and anti-Aspergillus precipitating antibodies by a new method: the radial immunoelectro-osmophoresis (RIEOP).

A new method of Immunoprecipitation-in-gel, the Radial Immunoelectro-osmophoresis (RIEOP) has been applied to detect precipitating anti-Aspergillus fumigatus antibodies and to study the antigens present in various antigenic extracts of this fungus. The results obtained with this method have been compared with those obtained when applying the Comparative Double Diffusion (CDD) and the Immunoelectro-osmophoresis (IEOP). The data presented prove that the RIEOP method is more sensitive than CDD and the IEOP in: (1) detecting precipitating anti-Aspergillus antibodies, since (a) precipitating bands are detected with higher serum dilutions, and (b) when using undiluted serum, the number of precipitating bands obtained by RIEOP is higher; and (2) studying antigens present in the antigenic extracts, since (a) the number of antigens detected by RIEOP is higher than that by CDD, and (b) identity/non-identity reactions can be studied among the antigens present in the various extracts.